This invention relates generally to valve operating mechanisms for use in internal combustion engines and, more particularly, to an oscillating rocker arm assembly and subassembly having rolling members.
Typically, a rocker arm assembly with rolling members is supported on a support shaft mounted perpendicularly on a support stud extending from the head of the engine. The rocker arm is pivoted on the support shaft, which serves as an inner raceway, by means of drawn cup needle roller bearings mounted on the rocker arm. Alternatively, a bearing sleeve may be mounted on the support shaft to provide the inner raceway, permitting use of a noncylindrical support arm and facilitating the use of powder metal forming.
Because of inherent manufacturing variations and deflections that occur during rocker arm operation, it is difficult to obtain even loading along the length of the rolling members with present rocker arm assemblies. Misalignment of rocker arm assembly elements causes the rolling members to carry a disproportionate radial load at one end, shortening the service life of the rocker arm assembly. Accordingly, there is a need to provide a rocker arm assembly that effects a more even distribution of radial load along the length of the rolling members when such misalignment occurs.
The foregoing illustrates limitations known to exist in present rocker arm bearing assemblies. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.